Safety device for presses and the like



Febn 16, 1943. L. D. JAMES; l u' SAF'ET'XV` DEVICE EUR PRESSES AND THELIKE Filed Nov. 1, 1941 .l k2 sheets-sheet 1- FIGA-' i' FISE- I LamuZIJ/#Mss 'BYL Qaeda?. 1r-

Feb. '16, 1943. L, Q JAMES' y 2,311,441

SAFETY DEVICE FOR PRESSES .AND THE LIKE OFF IC 2,311,441 SAFETY DEVICEFon raEssEs AND THE LIKE 'I'his invention relates to improvements insafety devices for presses and the like, and has for a principal objectthe provision of a beam of light spanning the zone which the operator-shands traverse when putting material into and/or removing material fromsaid press, and

'electronically controlled mechanism eiective while said light beam isinterrupted for preventing said press from operating.

Another object of the invention is the provision on a punch press or thelike of a photo-electric cell, a beam of light impinging upon said celland spanning the zone which the operators hands traverse, an amplifierconnected to said cell, and mechanism for disabling the clutch rod ofsaid press under control of said amplifier when said beam is interruptedby the operators hands.

A further object ofthe invention is the provision on a punch press, of asource of light span- 'ning the operative zone of the press, aphotoelectric cell amplifier unit adapted to receive said light, saidlight being adapted to be interrupted by the operators hands, a relaycontrolled by said amplifier, and a solenoid the energization of whichis controlled by said relay, means in the clutch rod of said pressadapted when in one position to transmit motion from the said pedal tothe clutch of said press, and adapted when in another position to movefreely without transmitting the motion to said clutch, said solenoidbeing adapted to shift said means to said lastmentioned arrangement whensaid cell is deprived of light.

Yet another objectV of the invention is the provision in the solenoidcircuit of a safety device for punch presses, of switching meansassociated with the clutch pedal of said press for enabling saidsolenoid circuit when said pedal is depressed.

. Other objects and advantages of the invention will be apparent tothose skilled in the art.

Referring now to the drawings:

Figure l is a side elevation of the mechanis interposed in the clutchrod of a punch press;

Figure 2 is an elevation of said mechanism as seen along the line 2--2of Figure 1;

VFigure 3 is a sectional View taken along the line 3-3 of Figure 1; i

Figure 4 is a front elevation of a punch press showing the applicationthereto of the new and improved safety device;

Figure 5 isan end elevation of the'press shown in Figure 4; s

Figure 6 is a side view of an over-riding control associated with theclutch pedal of the press;

Figure 7 is an elevation of the-arrangement shown in Figure 6, as seenvalong the line 'l--l therein; and

Figure 8 is a circuit diagram of the electrical control of the safetydevice.

Referring first to Figures 4 and 5, the punch press I0 is providedwiththe usual clutch II and clutch pedal I2. The rod leading from the clutchpedal i2 to the clutch II is divided into a lower portion I3 and anupper portion I4. The clutch pedal I2 has its pivotal support I6 carriedon the bracket I5, and the spring I1 urges the clutch pedal upwardly toits normal position.l

The mechanism to be now described is interposed between the lowerportion I3 of the clutch rod and the upper portion I4.

Referring now to Figure 1, the upper rod I4 has secured thereto a plateI8 by means of rivets I9 or any other suitable means. The plate I8 hasformed therein an L-shaped slot, the long leg 20 of which is verticaland the short leg 2| of which is horizontal.

The lower rod I3 has secured to its upper end, plates 22 and 23. Theseplates may be secured to the rod I3 in any suitable'manner, for exampleby means of rivets 24, and in order to position the plates in spacedrelation to each other, the rod I3 may be interposed therebetween. Apivot pin 25 extends through the plates 22 and 23 and has pivotallymounted thereon a roller 2B which is positioned within the Llslot in theplate I8.

The roller 2B is normallypositioned in the short leg 2l of the L-slot,due to the urge of the spring2l which is secured to a collar clamp 28 onthe lower rod I3 and to a xed point 29 on the body of thepress. l i-Also secured to the' upper .end of the rod I3 is a plate 3U. This plateis preferably secured to the rod by means of the rivets 24 hereinbeforementioned. A vertical slot 3l is formed inthe plate 3U, and positionedin this slot is a pin 32 carried by the yoked end 33 of the solenoidplunger 34. A solenoid winding 35 is associated with the plunger 34, andwhen the same is en; ergized, in a manner to be hereinafter described,the plunger 34 is moved to the right as viewed in Figure l, thereby'moving the lower rod I3 and the members associated therewith to theposition shown in dot-dash lines. This brings the roller 26 to theposition 26a so that if the clutch pedal lower rod I3 to the left andthe roller 26 assumes its normal position in the short leg 2 I of theslot, so that when the clutch pedal I2 is operated the motion will betransmitted to the clutch.

Referring again to Figures 4 and 5, an adjustable bracket 36 is securedtc one side of the press, and a second adjustable bracket 31 is securedto the other side of the press. Adjustably mounted on the bracket 36 isa housing 38 which carries the exciting lamp 39. This housing includessuitable lenses for throwing a cencentrated beam of light across thezone which the operators hands traverse in feeding material to and/orremoving material from the dies.

Adjustably mounted on the bracket 31 is a housing 40 which may contain,in addition to the photo-electric cell 4I, (Figure 8), an amplifier tubeV, the necessary circuit constants and a relay 42 for controlling thesupply of current to the solenoid winding 35.

By having the photo-electric cel housing 40 and the exciting lamphousing 38 adjustable on the body of the press, I am enabled to positionthese elements so that regardless of the size and height of the die, thebeam of light may always be set to traverse the operative zone.

Referring now to Figures 6 and 7, it will be noted that the bracket I5,which carries the pivotal support I6 of the clutch pedal arm I2, alsocarries a switching device 413 which may be one of the type whichoperates on very slight movement of the operative button 44. Thisoperative button is engaged when the clutch pedal I2 is in its upper ornormal position, and is immediately disengaged when the clutch pedal I2is depressed.

The switch 43 has its contacts normally open and these contacts includedin the solenoid circuit enable same when the clutch pedal I2 moves a fewthousandths of an inch. This, of course, is before the clutch canpossibly engage, `and the action of the solenoid causes the roller 26 toshift to the position 26a and makes it impossible for the motion to betransmitted from the lower rod I3 to the upper rod I6. This, of course,is predicated upon the premise that the beam of light is interrupted bythe operators hand or hands, and since it is impossible to engage theclutch when the operators hands are interrupting the beam of light, itis impossible for the operator to get his hands hurt or mangled.

Although I have herein shown and Adescribed by way of example apreferred embodiment of the invention, it is obvious that many changescan be made in the arrangement herein shown and described withoutdeparting from the spirit of the invention as set forth in the annexedclaims.

What is claimed is:

1. In a safetydevice4 for a press or the like,

carrying an inverted L shaped slot and a second member having meansprojecting into said slot, normally lying in the horizontal leg thereofand fc rming a normally positive linkage adapted to transmit motion fromsaid pedal to said means, electrically actuated means fo:` shifting saidsecond member to bring its means into the vertical leg of said slot,thereby introducing a lost motion in said linkage to prevent motion frombeing transmitted to said means from said pedal, a beam of lighttraversing the operative zone of said press, and-control means includinga photon Velectriclcell for energizing said electrically actulated`means when said cell is deprived of light having a pedal and meanscontrolled thereby, an.` operative rod therebetween including a memberfrom said beam.

2. In a safety device for presses or the like each including a pedal andhaving means controlled thereby, an operative rod therebetween dividedand having interposed between the parts thereof slot and pin meansforming a normally positive linkage adapted to transmit motion from saidpedal to said means, electrically actuated means for shifting therelative relation of said slot and pin means, th'ereby introducing alost motion in said linkage to prevent motion from being transmitted tosaid means from said pedal, a photoelectric cell on one side of saidpress, a source of light positioned on the opposite side of said pressand adapted to throw a beam crossing the operative zone of said pressand impinging upon said cell, an amplifier connected to said cell, and arelay controlled by the output of said amplifier for connecting saidelectrically actuated means to a sourceof current when said cell isdeprived of light from said beam.

3. In a safety device for a pu'nch press including a pedal and a clutchto be controlled thereby, means connecting said pedal to said clutchincluding a positionable member having a lateral projection and a secondmember having a trackway therein embracing said projection, the latternormally lying in a horizontal portion of said trackway and forming anormally positive linkage adapted to transmit motion from said pedalto`said clutch for actuating the latter, electrically actuated means forshifting said positlonablc member and moving said projection to anonhorizontal portion. of said trackway and thereby rendering saidpositive linkage ineifective and preventing motion from beingtransmitted to said clutch when said pedal is depressed, means forthrowing a beam of light across the front of said press cutting theoperative zone of the latter, and control means including a lightsensitive cell for energizing said electrically actuated means whensaidcell is deprived of light from said beam.

4. In a safety device for presses or the like each including a pedal anda clutch to be controlled thereby, a rod connected to said clutch and,extending downwardly, a second rod con nected to said pedal andextending upwardly, linkage means partly carried by said first rod andpartly carried by said second rod for normally causing said rods to movein unison when said pedal is depressed, said linkage means including apositionable member associated with one -,of said rods and having alateral projection and a second member having a trackway thereinembracing said projection, the latter normaliy lying in a horizontalportion of said trackway, electrically actuated means for shifting saidpositionable member and moving said projection to a non-horizontalportion of said trackway` and permitting said second rod to move Withouttransmitting its motion to said first rod when said clutch pedal isdepressed, an exciting lamp for throwing a beam of light across theoperative zone of said press, and photo- .lectric means normallyreceiving light from said beam and adapted when deprived of said lightto control the supplying of energy 'to said electrically actuated means.

5. In a safety device for a punch press or the like including a pedaland a clutch to be controlled thereby, a rod connected to said clutchand extending downwardly, a second rod connected to said pedal andextending upwardly,

carrying a roller which is normally positioned in said horizontal slot,electrically .actuated means for moving one of said members with respectto the other for bringing said roller in registration with said verticalslot and thereby preventing motion from being transmitted from the saidpedal to said clutch, an exciting lamp for throwing a beam of lightacross the operative zone of said press. and photo-electric meansnormally receiving light from said beam and adapted when deprived ofsaid light, to control the supplying of energy to said electricallyactuated means.

6. In a safety device for a punch press or the like including a pedaland a clutch to be controlled thereby, linkage means between said pedaland said clutch comprised of a plate member having a slotformed thereinand a second member carrying a roller positioned in said slot, said slotincluding a substantially horizontal portion and non-horizontalportions, said roller being normally positioned. in said horizontalportion and adapted to be moved to said non-horizontal portion whencontrolled to prevent said clutch from being operated, electricallyactuated means for effecting control, an exciting lamp for throwing abeam of light across the operative zoneof -said press, photo-electricmeans normally receiving light from said beam and adapted when deprivedof said light to condition a circuit for supplying energy to saidelectrically actuated means, switching means included in said circuitand including an actuating member in contact with said pedal, saidswitch being normally open and adapted to close said circuit when saidpedal is moved.

LLOYD D. JAMES.

